Generally, this invention relates to a latch system for and techniques of resealably enclosing contents within a container through the use of a reusable latch device, and to a product-user safety system for and techniques of reliably indicating whether a container has been opened prior to sale. Specifically, the invention focuses on techniques for latching container openings using a latch apparatus (or device) such that manufacturing of the latch apparatus is rendered more efficient, and upon techniques for enhancing the safety of users of resealable containers through use of a tamper-resistant apparatus that operates to assure that a certain resealable container retains its original factory closure. The invention also focuses on a fluid tight seal that reduces the amount of fluid flow into and/or out of a sealed container. An additional focus is on a latch that affords improved flexing during engagement and disengagement, resulting in improved functional operation that is more acceptable to container users.
The desire to enclose container contents using a resealable (or recloseable) latch apparatus has been known in some industries for many years. In one basic form, the concept involves establishing a latch that operates to both close and open via a snap-type response to an applied force (a snap displacement-to-force response). The snap response refers to a displacement of engageable latch parts (such as positive engagement elements) in response to an applied force, wherein upon engaging (closing) and disengaging (opening) of corresponding engagement parts, there is observed a threshold displacement-to-force response. More specifically, during closing of the latch, there is, upon initial contact of the corresponding engageable latch elements that typically oppositely face one another, an increase in the applied force that results in no (or very little) relative displacement of the engageable latch elements. This force increases until it reaches a threshold value, at which point there is a “snap” response and there is observed a significant relative displacement of the engageable latch parts—indeed, this displacement typically is the maximum allowable displacement and may enable (in combination with other mechanical effects) any attached container parts to be retained in a closed position. During opening of the closed latch apparatus, a similar threshold force response may be found—the initial application of the force (a tension force as applied on the engaged latch parts) intended to open the latch does not result in relative displacement of engaged latch parts (except for perhaps some initial displacement associated with “play” in the engaged latch apparatus). The applied force increases until a threshold value is reached, at which point a relative displacement (a yielding) sufficient to disengage the latch parts and open the latch apparatus is observed. Importantly, this is unlike embodiments of patents such as U.S. Pat. Nos. 3,063,487 and 5,472,281, inter alia, where such a snap displacement-to-force response is not shown.
Often, such a tension yieldable, resealable closure apparatus is used on a container that is designed for squeeze-activated opening. Essentially, with such a squeeze-openable container, (or squeeze-openable latchable container if it includes a latch) the container is designed such that the application of a compressive force to the end edges of a closed (or shut) container opening is translated into a tension force that acts to force open the container opening that is in a closed position.
A significant problem associated with such tension yieldable, engageable, resealable latches is not necessary in their operation, but instead manifests itself in the manufacturing phase. Many designs (see, e.g., U.S. Pat. Nos. 2,520,467, 3,110,335, 3,176,743, 3,280,870, 3,426,814 and 5,623,980, inter alia) have one side of the latch apparatus different from the other side of the latch apparatus. Of course, the manufacture of a second side of such a latch cannot be conducted using precisely the same apparatus (such as a mold) that is used to manufacture the first side of such a latch. It is precisely this manufacturing limitation or inefficiency that at least one embodiment of the present invention addresses.
The desire to assure or enhance the safety of users of contained products by assuring or enhancing the safety of the contents of unopened, resealable containers has also been known in some industries for years. What may be termed a tamper-resistant seal found on, e.g., plastic soda bottles, is well known to consumers and in the bottling industry. However, there appear to be no apparatus that act to assure the unopened condition of squeeze-openable containers that have reusable latches. There also appear to be no apparatus that act to assure the unopened condition of a container having a low perimetrical aspect ratio, linear reusable latch (where linear in this context indicates non-circular, although the latch axis may have a slight curve and certainly may be straight). Further, there appear to be no apparatus that act to assure the unopened condition of a container whose latch is made of two substantially identical side parts.
The desire to assure the unopened condition of container contents, or more generally, to simply prevent the transfer of fluid across a container membrane, has been known in certain industries for many years, as has the desire to provide a reusable latch that is operable to repeatedly open and close a container. However, design limitations of existing seals and latches compromise their applicability and functionality. At least one embodiment of the invention addresses each of these needs.